Liquid hydrocarbon composition and additives therefor



United States Patent 3,226,322 LIQUID HYDROCARBUN COMPOSTTIGN AND ADDITIVES THEREFOR Glenn Fuller, Berkeley, Calif., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 28, 1961, Ser. No. 162,924 7 Claims. (Cl. 25232.7)

This invention relates to improved functional organic compositions and additives therefor. More particularly, the invention relates to compositions of the type of fuel and lubricant compositions having improved properties.

In general, hydrocarbon compositions are doped with various oil-soluble compounds, namely, stabilizers and anti-oxidants, such as phenolic compounds, e.g., alkyl phenols and bisphenols; detergent and corrosion inhibitors such as metal organic carboxylates, phenates, phosphates, sulfonates and thiocarbamates; anti-wear and extreme pressure compounds such as esters of carboxylic acids or phosphorus acids such as partial esters of fatty acids and polyhydric alcohols or alkyl or aryl phosphites or phosphates, or [free fatty acids and sulfur derivatives thereof such as C1048 fatty acids (oleic or stearic acids) and sulfurized unsaturated fatty acids, e.g., sulfurized oleic acid. However, these compounds when used in liquid hydrocarbons, such as lubricating oil compositions which are subjected to high temperatures and pressures break down and fail to impart their expected desired properties under these extreme conditions.

It has now been discovered that liquid hydrocarbon compositions are improved with respect to stability, wear inhibition and extreme pressure properties and contribute to minimizing octane requirement increase when used in an internal combustion engine, and the like by incorporating therein a minor amount of an oil-soluble polysulfide of a phosphorus-containing compound having the general formula:

XR1 (I) wherein R is an oil-soluble straight-chain alkyl radical having from to 18 carbon atoms, the Rfs are the same or different groups selected from hydrogen, hydrocarbyl, or amine, preferably an alkylamine, R is hydrogen or C alkyl radical, the Xs are independently chalcogen atoms having an atomic number of from 8 to 16, such as oxygen or sulfur and y is an integer of from 2 to 4, preferably 2. Preferred compounds of the general Formula I have the following formula:

0 0R1 C 10-15 alkyl-S-S-C 112-;

0R1 (II) The R s are as defined above in (I) or 0 OH-(A) Cums alkyl-S--SCHz-P OH (III) O OH-(A) CID-1S alkyl-SSCHzP OH-(A) (IV) ice A is an aliphatic amine, preferably a primary or secondary amine, such as C primary straight chain amines, e.g., octylamine, laurylamine, stearylamine, etc., or branched chain primary aliphatic amines, e.g., t-C alklamine, such as t-cgH qNHz, t-C15H31NH Or I'C12H25NH2 t0 t-C15H31NH2 '01 C5 13 secondary amines, such as diamylamine, di-Z-ethylhexylamine, didecylamine, or mixtures thereof or polyvalent metal such as alkaline earth metals, e.g., Ca, Ba, Sr.

The polysulfides of alkylphosphono compounds, e.g., 2,3dithia or 2,3,4-trithia or 2,3,4,5-tetrathiaalkyl phosphonic compounds are prepared by reacting a mercaptide having at least 6 carbon atoms with a halomethylphosphono compound such as chloromethylphosphonic acid or a dialkylchloromethylphosphonate of their thio-derivatives in the presence of elemental sulfur and a suitable solvent, such as an aqueous alcoholic solution, at rereflux temperature and under inert conditions until the reaction is completed which normally requires from 1 to about 5 days. The mercaptans include aliphatic mercaptans, such as hexyl, :octyl, decyl, dodecyl, octadecyl mercaptans, and the like. Instead of the mercaptans, the mercaptides can be used such as the alkali metal (Na or K) mercaptides of the above compounds. Suitable halomethylphosphonic compounds include chloromethylphosphonic acid, mono or dihydroearbyl chloromethylphosphonates, e.g., mono or dibutyl chloromethylphosphonate, mono or di-Z-ethylhexyl chloromethylphosphonate, mono or dilauryl chloromethylphosphonate, mono or diphenyl chloromethylphosphonate, mono or dicyclohexylchloromethylphosphonate, mono or dibenzyl chloromethylphosphonate, dibutyl dithiochloromethyl phosphonate, diphenyl chloromethyl dithiophosphonate, dibutyl chloromethyltrithiophosphonate, alkali metal salts such as Na and K salts of chloromethylphosphonic acid, Na and K salts of monobutyl chloromethylphosphonic acid, Na and K salt of monodecyl chloromethylphosphonic acid and the like.

A preferred method of making the 2,3-dithia or 2,3,4- trithia or 2,3,4,S-tetrathiaalkylphosphonates is to react a mixture of a suitable mercapto compound, such as an alkali metal (Na or K) C1048 alkyl mercaptide, elemental sulfur and a chloromethylphosphonic acid, its ester or salt, e.g., an alkali metal (Na or K) salt of chloromethyl phosphonic acid in an alcoholic solution under reflux conditions and under an inert atmosphere to form the alkylpolythiamethylphosphono compound, e.g., the alkali metal salt of thiaalkylphosphonic acid. The salt, for example, is then treated with a strong acid such as hydrochloric acid to spring the free dithiaalkylphosphonic acid, which can be converted into desired partial or full esters or polyvalent metal salts or amine salts for use as oil, fuel and grease additives as well as other uses. If the partial or full ester are the desired end product then instead of starting with the alkylpolymercaptomethylphosphonate, the ester can be used such as the mono or dialkyl ester of chloromethylphosphonic acid.

The following examples illustrate the preparation of additives for use in accordance with the present invention.

Example I .-M onobutyl 2,3-dithiatridecylphosphonate About 206 grams of dibutyl 2,3-dithiatridecylphosphonate was charged into a flask containing aqueous solution of KOH in ethanol and the mixture was reluxed for 48 hours. The reaction product was acidified with dilute HCl and extracted with ether, washed and dried and the recovered product was monobutyl 2,3-dithiatridecylphosphonate, an oil-soluble product having good EP properties.

Example Il.-Decyl 2,3-dillziamethylphosphonic acid Stoichiometric amounts of the potassium salt of decyl mercaptan, elemental sulfur and the potassium salt of monochloromethylphosphonic acid were dispersed in an aqueous solution of ethanol and the mixture was refluxed at 78 C. under a nitrogen atmosphere for about 1 day. The potassium decyl-2,3-dithiamethylphosphonate was then treated with strong hydrochloric acid to spring the acid product which was recovered by extraction with ether. The final product was decyl 2,3-dithiamethylphosphonic acid.

Example III.Di-2ethylhexylamine 2,3-diflziatridecyl phosphonate Di-Z-ethylhexylamine salt of 2,3-dithiatridecylphosphonic is prepared by reacting the product of Example II with di-Z-ethylhexylamine in an amount sufficient to completely neutralize both acid groups, at about 50 C. in an alcoholic solution and thereafter recovering the amine salt from the alcoholic solution.

The following additional compounds may be prepared: 2,3-dithiaundecylphosphonic acid, 2,3,4-trithiahexadecylphosphonic acid, omega-cyclohexyl-Z,3-dithiapropylphosphonic acid, omega-phenyl-2,3-dithiabutylphosphonic acid, omega-phenyl-2,3,4-trithiabutylphosphonic acid, dibutyl 2,3,4-trithiatetradecylphosphonate, omega-phenyl-2,3-dithiatridecyl acid phosphonate, dithiooctylcyclohexyl-2,3,4-trithiamethylthiophosphonate, dioctyl amine dodecylmercaptomethylphosphonate, dioctadecylarnine omega-phenyl-Z,3-dithiabutylphosphonate, tert-octadecylamine 2,3-dithiapentadecyl phosphonate, and mixtures thereof.

The additives of this invention are believed to be novel compounds. They can be used in amounts of from about 0.1% to about 25%, preferably from about 0.5% to about 5.0% by weight in various base lubricants, greases and fuels.

Polysulfides of alkylphosphono compounds of this invention are outstanding additives for various liquid hydrocarbon products, such as natural and synthetic hydrocarbon lubricating oils, greases, fuels (gasoline, kerosene, gas oil, burner fuel oil), asphalts, waxes, slushing oils, industrial oils, e.g., metal working and drawing oils, quenching oils, textile oils, hydraulic oils, dielectric compositions and other industrial oils. They are particularly outstanding when added in small amounts to lubricating oils and lubricating compositions to impart antioxidant or extreme pressure or anti-wear properties to such materials. Also, these additives are useful additives for gasoline, fuel oils, and other light oil products.

Lubricating oils useful for the preparation of compositions of this invention can be one or more of a variety of synthetic oils or natural hydrocarbon oils having a viscosity range of from 50 SUS to 100 F. to 250 SUS at 210 F. (SAE viscosity number ranging from SAE W to SAE 90). The natural hydrocarbon oils can be obtained from paraflinic naphthenic, asphaltic or mixed base crudes, and/or mixtures thereof. Synthetic oils include polymerized olefins, alkylated aromatics, isomerized waxes, copolymers of alkylene glycols and alkylene oxides (Ucon fluids) which are described in US. Patents 2,425,755, 2,425,845 and 2,774,733 such as Ucon 50 HB170, Ucon 50 HB660 or Ucon LB 550X and which are copolymers of ethylene and 1,2-propylene oxides, the mono and diols, as well as their ester derivatives; organic esters of aliphatic dibasic acids such as di-2-ethylhexyl sebacate or di-2ethylhexyl adipate and the like. The hydrocarbon oils may be blended with fixed oils such as castor oil, lard oil and the like and/ or synthetic oils as (A) (SAE 10W) (B) (SAE 30) Pour point, F Flash, F

Other suitable oils are the gas turbine lube oils having the following properties:

Grade 1010 1055 Flash, 000, F 300 465 Pour, F 10 0 Viscosity, SUS at F 59. 4 530 Neutral Number 0. 02 0.01 Ash None None The following compositions are illustrative of the invention, the percentages being by weight, of the indicated additive or additives with the remainder being essentially the base.

Compositions of the present invention such as compositions A and D exhibit excellent extreme pressure properties when tested in the four-ball extreme pressure tester described in Engineering, July 13, 1933, volume 136, and operated at 40 kg. and 1340 r.p.m. When these compositions were compared with mineral oils containing about 2% each of such well known extreme pressure additives as tricresyl phosphate (composition X), zinc octyl dithiophosphate (composition Y), or sulfur (composition Z), the compositions of the present invention are superior. Thus compositions A and D reduce wear by at least 10% over compositions X, Y and Z and compositions of the present invention were much more stable both under storage and dynamic conditions than the compositions X, Y and Z.

The polysulfides of alkylphosphono compounds of this invention are useful also for providing superior loadcarrying properties for lubricating oils which contain rninor amounts of other agents, such as silicone antifoaming agents, alkylphenol antioxidants, polyacrylate ester viscosity-index improvers, long chain fatty acids such as lauric and oleic acids, oiliness agents and the like.

I claim as my invention:

1. A mineral lubricating oil composition consisting essentially of a major amount of mineral lubricating oil and from about 0.5 to about 5% of a 2,3-dithiamethyl phosphono compound selected from the group consisting of C alkyl 2,3-dithiamethyl phosphonic acid and an alkylamine salt of C1048 alkyl 2,3-dithiamethy1 phosphonic acid.

2. A mineral lubricating oil composition consisting essentially of a major amount of mineral lubricating oil 5 and from about 0.5% to about 5% of di-2-ethylhexylamine salt of monobutyl 2,3-dithiatridecy1 phosphonate.

3. A mineral lubricating oil composition consisting essentially of a major amount of mineral lubricating oil and about 0.5% to about 5% of t-C H NH to tC24H49NH2 salt of monobutyl 2,3-dithiatridecyl phosphonate.

4. A mineral lubricating oil composition consisting essentially of a major amount of mineral lubricating oil and and from about 0.5 to about 5% of a C1048 alkyl 2,3- dithiamethylphosphonic acid.

5. A mineral lubricating oil composition consisting essentially of a major amount of mineral lubricating oil and from about 0.5 to about 5% of an alkylamine salt of C alkyl 2,B-dithiamethylphosphonic acid.

6. A mineral lubricating oil composition consisting essentially of a major amount of mineral lubricating oil and from about 0.5% to about 5% of 2,3-dithiatetradecylphosphonic acid.

E 7. A mineral lubricating oil composition consisting essentially of a major amount of mineral lubricating oil and from about 0.5 to about 5% of tert-octadecylamine salt of 2,3-ditl1iatetradecylphosphonic acid.

References Cited by the Examiner UNITED STATES PATENTS 2,157,452 5/1939 Humphreys 252-466 2,174,019 9/1939 Sullivan 252--49.8 2,535,174 12/1950 Tawney 260461 2,629,731 2/1953 Harman 260461 2,724,718 11/1955 Stiles et al. 260-461 2,857,305 10/1958 Birum 252-467 3,112,269 11/1963 Calhoun et al. 252- 466 3,112,271 11/1963 Calhoun 260'-461 3,114,710 12/1963 Calhoun 25232.7

DANIEL E. WYMAN, Primary Examiner.

JULIUS GREENWALD, Examiner. 

1. A MINERAL LUBRICATING OIL COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF MINERAL LUBRICATING OIL AND FROM ABOUT 0.5% TO ABOUT 5% OF A 2,3-DITHIAMETHYL PHOSPHONO COMPOUND SELECTED FROM THE GROUP CONSISTING OF C10-18 ALKYL 2,3-DITHIAMETHYL PHOSPHONIC ACID AND AN ALKYLAMINE SALT OF C10-18 ALKYL 2,3-DITHIAMETHYL PHOSPHONIC ACID. 